1. Field of the Invention
The present invention relates to circuit interrupters generally and, more specifically, to those kinds of circuit interrupter having a trip mechanism including an automatic trip assembly for generating a magnetically-induced tripping operation.
2. Description of the Prior Art
Molded case circuit breakers and interrupters are well known in the art as exemplified by U.S. Pat. No. 4,503,408 issued Mar. 5, 1985, to Mrenna et al., and U.S. Pat. No. 5,910,760 issued Jun. 8, 1999 to Malingowski et al., each of which is assigned to the assignee of the present application and incorporated herein by reference.
A continuing industry objective with respect to many types of circuit interrupters is to be able to reduce the size and/or footprint of the interrupter housing while at the same time providing the same or improved performance capabilities. A major advantage of creating such a "smaller package" is that it provides increased flexibility in installation. However, a consequence of this objective is that the internal space constraints of such interrupters have become much more limiting, posing certain design obstacles that need to be overcome.
Circuit interrupters advantageously provide for automatic circuit interruption (opening of the contacts) when an overcurrent condition is determined to exist. One way of determining whether or not an overcurrent condition exists is to provide a trip mechanism with an automatic trip assembly that reacts to a magnetic field generated by the overcurrent condition. In such circuit interrupters, the reaction to the magnetic field is often in the form of a movement of an armature that, in turn, sets in motion a tripping operation.
In order to enable such movement of the armature, the prior art provides complicated structures which, unfortunately, occupy a relatively significant amount of internal space within the interrupter. It would be advantageous if a less complicated, more direct way existed by which to provide for movement of the armature and that could be effectively employed within circuit interrupters having the aforementioned space constraints. It would also be advantageous if such a way would enable the armature to easily be installed during the assembly process of the interrupter.